A turbine includes a transition portion where a combustor section joins a transition piece. The combustor section includes a combustor liner having an aft end that joins a transition piece body of the transition piece. A reduced thickness portion at the aft end of the combustor liner is covered by a cover sleeve to form an air flow passage on the aft end of the combustor liner. Apertures in the forward portion of the cover sleeve allow cooling air to flow into air flow passage. A plurality of turbulators project radially outward from the reduced thickness portion of the combustor sleeve towards said cover sleeve. An arch shaped resilient seal structure is positioned between the cover sleeve and the transition piece body. Supports formed on the reduced thickness portion of the combustor liner bear against the inside of the cover sleeve to prevent the cover sleeve from deforming inward due to a force applied by the seal, thereby ensuring that the air flow passage remains open.